1. Technical Field of the Invention
The invention is related to the field of telephone systems, and more particularly, the switching systems within the public land mobile networks (PLMN) and the land based wireline telephone networks.
2. Description of the Related Art
Current telephone systems including cellular telephone systems are increasingly becoming a powerful and efficient medium for coordinating and carrying out illegal activities. Accordingly, governments have a need to monitor the activities and phone calls of particular suspects. Given some of the recent horrific acts of terrorism, the government's need to monitor certain phone calls is greater than ever. Given today's information technology, as well as the increased mobility of people on a worldwide basis, however, monitoring the activities and conversations of certain individuals has become increasingly problematic. One day, a suspect might be in Europe. On another day, the same suspect might be either in the United States or in a third world nation. Because special equipment is required to monitor telephone conversations, it is difficult to monitor many telephone conversations given the ease with which anyone, including a suspect, can travel around the world.
There are several obstacles to monitoring calls of an individual traveling around the world. First, monitoring equipment would have to be installed worldwide. Clearly, the expense of this solution is very high. Second, there may well be legal obstacles to importing monitoring equipment into some countries and to removing taped conversations.
Moreover, it is difficult to monitor a conversation being carried by a mobile station as it passes geographic areas which are served by different mobile switching centers and base station systems. In such a scenario, one conversation is partially recorded by each of multiple monitoring devices. Combining each recorded part to create one monitored conversation would be difficult and labor intensive.
What is needed therefore is a system and a method for efficiently monitoring specified telephone systems, including cellular systems, regardless of the location of the specified telephonic device, in a way which is efficient and which overcomes potential legal difficulties associated with importing or exporting monitoring equipment. A system is needed which allows monitoring regardless of the phone location.